|Description||This article describes the steps to access a DNS Server on the other side of an IPsec Tunnel|
The DNS traffic on FortiGate is self-originating traffic, meaning it originated from FortiGate itself. See the administration guide for more information.
To fix this, assign an interface IP address to the IPsec tunnel interface.
For this, go to Network -> Interfaces.
After that, the DNS server will start working.